(1) Field of the Invention
The present invention relates to a pressure test apparatus for a double suction volute pump.
(2) Description of Related Art
Pressure tests are required for pressure vessels such as pump casings.
The following is a pressure test designed for a conventional storage pump to confirm that, under test conditions, the casing of the pump will not be destroyed and there will be no leakage of water. First, water is sealed within the casing of the pump, and then, the pressure in the casing is increased until it is about one and a half times as high as a discharge pressure (a shutoff pressure) for a zero-discharge operation.
A similar pressure test is also performed for the volute casing of a double suction volute pump. To prepare for the test, bolts are inserted through holes in flanges on upper and lower volute casing assembly sections, and O rings are sandwiched between the upper and lower volute casing, and the bolts are tightened to secure the upper to the lower volute casing. Then, to seal the thus prepared volute casing, a suction port, a discharge port, shaft seal parts and other ports are tightly closed, and a port through which water is to be introduced is prepared. Thereafter, for the test, water is introduced and the water pressure is increased until one and a half times as high as the shut-off pressure in both a suction chamber and a discharge chamber. Thus, the casing thickness for the suction chamber must be greater than that for the discharge chamber in order to withstand the test pressure because the suction chamber has the larger volume.
Patent Document 1: JP-A-7-318449
Patent Document 2: JP-A-8-28486
Patent Document 3: JP-A-11-236894
Patent Document 4: JP-A-11-303789
Patent Document 5: JP-A-2003-184786
Non-patent Document 1: JIS B8322